Radar apparatus and method for detecting object based on occurrence of event

ABSTRACT

An object detection radar apparatus is installed in a vehicle and is configured to detect an object. The object detection radar apparatus includes a transceiver configured to transmit a radar signal to the outside of the vehicle and receive a radar signal reflected from the object; a driving environment detector configured to detect a driving environment of the vehicle based on an operation status of the vehicle; an object detector configured to detect the object based on the received radar signal; and a controller configured to determine whether or not a predetermined event occurs based on the driving environment of the vehicle or a result of the detection of the object, and control signal characteristics of the transmitted radar signal or the received radar signal when the predetermined event occurs.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 USC 119(a) of Korean PatentApplication No. 10-2020-0184951 filed on 28 Dec. 2020, in the KoreanIntellectual Property Office, the entire disclosures of which areincorporated herein by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to a radar apparatus and method fordetecting an object based on the occurrence of an event.

BACKGROUND

An automotive radar functions to provide a driver with positioninformation of nearby vehicles and obstacles present in front, besideand behind the driver's vehicle. Also, the automotive radar may beinstalled in an autonomous vehicle and used to control the vehicle toperform autonomous driving and support safe driving.

In regard to this automotive radar, Korean Patent No. 10-0951529discloses a method for driving an ultra-wideband radar system forvehicle and an ultra-wideband radar system for vehicle.

Hereinafter, a conventional automotive radar will be described withreference to FIG. 1A to FIG. 1C.

Referring to FIG. 1A, a conventional automotive radar may detect anobject by transmitting radar signals from a vehicle 100 to a firstdetection range 110 covering a narrow and long area and a seconddetection range 120 covering a wide and short area. Each of the firstdetection range 110 and the second detection range 120 has a fixedmaximum detection range and angle, and the conventional automotive radartransmits radar signals alternately to the first detection range 110 andthe second detection range 120 at a regular time interval.

If the conventional automotive radar is a fast-chirp frequency-modulatedcontinuous wave (FMCW) radar which is greatly improved in rangeresolution compared with a general FMCW radar, the maximum detectionrange is determined based on the range resolution determined by thebandwidth of the radar signal transmitted from the FMCW radar and thenumber of samples for the radar signal to be received through ananalog-digital converter (ADC) included in the FMCW radar based on asingle chirp.

That is, the maximum detection range R_(max) is equal to ΔR·N_(R) anddetermined based on ΔR=C/2B (herein, C represents the speed of light, Brepresents the bandwidth, ΔR represents the range resolution and N_(R)represents the number of samples).

However, if N_(R) is constant, the conventional automotive radar islimited in the maximum detection range for a fixed range resolution. IfN_(R) is increased to overcome this, the maximum detection range can beincreased while maintaining the range resolution, but the memory usageis increased.

Also, referring to a waveform graph showing frequencies 131 over time130 in FIG. 1B, if N_(R) is increased, ΔT 132 increases, and as ΔT 132increases, the maximum unambiguous velocity of an object to be detectedusing a radar signal decreases. Further, if ΔT 132 increases, a cycletime increases as a waveform transmitting time 133 increases.

Recently, an automotive radar has been equipped with an imaging radarconfigured to perform spatial imaging. However, if a fixed maximumdetection range and angle is applied to the imaging radar requiring highresolution, it is impossible to detect an object at a long distance withhigh range resolution.

Referring to FIG. 1C, the imaging radar employs a multi-inputmulti-output (MIMO) scheme using a plurality of transmitter antennas(Tx) 140 to increase the angle resolution. However, the MIMO scheme hasa low maximum unambiguous velocity, which makes it difficult to detectan object having a high relative speed.

Accordingly, when detecting an object having a high relative speed, theimaging radar is subjected to a decrease in detection probability.

SUMMARY

In view of the foregoing, the present disclosure provides an objectdetection radar apparatus and method capable of transmitting a radarsignal to the outside of a vehicle, receiving a radar signal reflectedfrom an object, detecting a driving environment of the vehicle based onan operation status of the vehicle and detecting the object based on thereceived radar signal.

The present disclosure provides an object detection radar apparatus andmethod capable of determining whether or not a predetermined eventoccurs based the driving environment of the vehicle or a result of thedetection of the object and controlling signal characteristics of thetransmitted radar signal or the received radar signal when thepredetermined event occurs.

The problems to be solved by the present disclosure are not limited tothe above-described problems. There may be other problems to be solvedby the present disclosure.

According to an exemplary embodiment, an object detection radarapparatus that is installed in a vehicle and configured to detect anobject may include a transceiver configured to transmit a radar signalto the outside of the vehicle and receive a radar signal reflected fromthe object; a driving environment detector configured to detect adriving environment of the vehicle based on an operation status of thevehicle; an object detector configured to detect the object based on thereceived radar signal; and a controller configured to: determine whetheror not a predetermined event occurs based on the driving environment ofthe vehicle or a result of the detection of the object, and controlsignal characteristics of the transmitted radar signal or the receivedradar signal when the predetermined event occurs.

The above-described exemplary embodiments are provided by way ofillustration only and should not be construed as liming the presentdisclosure. Besides the above-described exemplary embodiments, there maybe additional exemplary embodiments described in the accompanyingdrawings and the detailed description.

According to any one of the above-described embodiments of the presentdisclosure, it is possible to possible to provide an object detectionradar apparatus and method capable of transmitting a radar signal to theoutside of a vehicle, receiving a radar signal reflected from an objectto detect the object, determining whether or not a predetermined event,such as preceding car following event or preceding car absence event,occurs based the driving environment of the vehicle or a result of thedetection of the object and controlling signal characteristics of thetransmitted radar signal or the received radar signal when thepredetermined event occurs.

It is possible to possible to provide an object detection radarapparatus and method capable of detecting a driving environment of avehicle based on an operation status of the vehicle, determining whetheror not a predetermined event, such as curve driving of the vehicle,occurs based on the detected driving environment of the vehicle andcontrolling signal characteristics of a radar signal when thepredetermined event occurs.

The imaging radar has required a lot of hardware resources to provide aspecification optimal for every case. However, according to any one ofthe above-described embodiments of the present disclosure, it ispossible to provide an object detection radar apparatus and methodcapable of reducing hardware resources to be consumed by changing aspecification for each case.

It is possible to possible to provide an object detection radarapparatus and method capable of improving the performance of a radarsensor for each case using limited resources.

It is possible to possible to provide an object detection radarapparatus and method capable of reflecting the requirements for anoptimal radar sensor so as to be applicable to an autonomous vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

In the detailed description that follows, embodiments are described asillustrations only since various changes and modifications will becomeapparent to those skilled in the art from the following detaileddescription. The use of the same reference numbers in different figuresindicates similar or identical items.

FIG. 1A is a depiction to explain a process of detecting an object usinga conventional automotive radar.

FIG. 1B is a depiction to explain a process of detecting an object usinga conventional automotive radar.

FIG. 1C is a depiction to explain a process of detecting an object usinga conventional automotive radar.

FIG. 2 is a block diagram illustrating the configuration of an objectdetection radar apparatus in accordance with an embodiment of thepresent disclosure.

FIG. 3 is an example depiction illustrating a medium-distance mode and along-distance mode in accordance with an embodiment of the presentdisclosure.

FIG. 4 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as curve driving of avehicle, occurs in accordance with an embodiment of the presentdisclosure.

FIG. 5 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as preceding car followingevent, occurs in accordance with an embodiment of the presentdisclosure.

FIG. 6 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as preceding car absenceevent, occurs in accordance with an embodiment of the presentdisclosure.

FIG. 7 is a flowchart showing a method for detecting an object by theobject detection radar apparatus in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Hereafter, example embodiments will be described in detail withreference to the accompanying drawings so that the present disclosuremay be readily implemented by those skilled in the art. However, it isto be noted that the present disclosure is not limited to the exampleembodiments but can be embodied in various other ways. In the drawings,parts irrelevant to the description are omitted for the simplicity ofexplanation, and like reference numerals denote like parts through thewhole document.

Throughout this document, the term “connected to” may be used todesignate a connection or coupling of one element to another element andincludes both an element being “directly connected” another element andan element being “electronically connected” to another element viaanother element. Further, it is to be understood that the term“comprises or includes” and/or “comprising or including” used in thedocument means that one or more other components, steps, operationand/or the existence or addition of elements are not excluded from thedescribed components, steps, operation and/or elements unless contextdictates otherwise; and is not intended to preclude the possibility thatone or more other features, numbers, steps, operations, components,parts, or combinations thereof may exist or may be added.

Throughout this document, the term “unit” includes a unit implemented byhardware and/or a unit implemented by software. As examples only, oneunit may be implemented by two or more pieces of hardware or two or moreunits may be implemented by one piece of hardware.

In the present specification, some of operations or functions describedas being performed by a device may be performed by a server connected tothe device. Likewise, some of operations or functions described as beingperformed by a server may be performed by a device connected to theserver.

Hereinafter, the present disclosure will be explained in detail withreference to the accompanying configuration views or process flowcharts.

FIG. 2 is a block diagram illustrating the configuration of an objectdetection radar apparatus in accordance with an embodiment of thepresent disclosure. Referring to FIG. 2, an object detection radarapparatus 200 may include a transceiver 210, a driving environmentdetector 220, an object detector 230 and a controller 240. Herein, theobject detection radar apparatus 200 according to the present disclosuremay include an imaging radar. The term “imaging radar” refers to a radarconfigured to transmit microwaves to an object (target), acquirereflection waves reflected and returning from the object (target) insequence depending on the distance and acquire information about thepresence and shape of the object. The imaging radar may be installed onthe roof, number plate, bumper or front mirror of a vehicle.

The transceiver 210 may transmit a radar signal to the outside of avehicle and receive a radar signal reflected from an object. Forexample, the transceiver 210 may transmit a medium- and long-distancerange radar signal to the outside of the vehicle.

For example, the transceiver 210 may transmit a radar signal to amedium-distance range corresponding to a medium-distance mode so as toreach a distance of, for example, 120 meters (m) from the vehicle. Also,the transceiver 210 may transmit a radar signal to a long-distance rangecorresponding to a long-distance mode so as to reach a distance of, forexample, 300 m from the vehicle. Here, the medium-distance mode and thelong-distance mode may be in an activation state even without anactivation trigger from when the vehicle starts driving on the roaduntil the vehicle stops driving.

The medium-distance mode and the long-distance mode will be described indetail with reference to FIG. 3.

FIG. 3 is an example depiction illustrating a medium-distance mode and along-distance mode in accordance with an embodiment of the presentdisclosure. Referring to FIG. 3, a detection range in a medium-distancemode 301 may include a medium-distance range and a detection range in along-distance mode 302 may include a long-distance range.

An antenna structure 310 in the medium-distance mode 301 and thelong-distance mode 302 may include a plurality of transmitter antennasTx arranged at regular horizontal and vertical intervals in a diagonaldirection and a plurality of receiver antennas Rx arranged in parallelwith each other in a horizontal direction based on an azimuth axis of adriving direction of the vehicle.

For example, a bandwidth 311 may be 500 MHz for the medium-distance mode301 and 200 MHz for the long-distance mode 302.

For example, a max range (equal to maximum detection range) 312 may be120 m for the medium-distance mode 301 and 300 m for the long-distancemode 302.

For example, a max velocity 313 of an object to be detected using aradar signal in the medium- and long-distance modes 301 and 302 may be250 kilometers per hour (kph), and a field of view (FoV) 314 for themedium- and long-distance modes 301 and 302 may be ±45/±16 deg.

For example, a range resolution 315 may be 0.3 m for the medium-distancemode 301 and 0.75 m for the long-distance mode 302.

For example, a range accuracy 316 may be 0.1 m for the medium-distancemode 301 and 0.375 m for the long-distance mode 302.

For example, the medium- and long-distance modes 301 and 302 may have avelocity resolution 317 of 0.4 kph and a velocity accuracy 318 of 0.2kph.

For example, the medium- and long-distance modes 301 and 302 may have anangle resolution 319 including an azimuth angle of 2.8 deg or less andan elevation angle of 5.6 deg, an angle accuracy 320 of 0.5 deg and acycle time of 67 milliseconds (ms).

Here, the medium-distance mode 301 and the long-distance mode 302 may beperformed alternately based on a cycle time 321. For example, if thecycle time is 67 ms, the medium-distance mode 301 and the long-distancemode 302 may be performed alternately at an interval of 67 ms.

Referring to FIG. 2 again, the driving environment detector 220 maydetect a driving environment of the vehicle based on an operation statusof the vehicle. Here, the operation status of the vehicle may refer tothe status for driving forward and backward, turning left and right orthe like depending on, for example, a steering angle or a yaw rate ofthe vehicle.

The object detector 230 may detect the object based on the receivedradar signal. For example, the object detector 230 may detect an objectrelated to a nearby vehicle, obstacle or person located in the vicinityof the vehicle based on the received radar signal.

The controller 240 may determine whether or not a predetermined eventoccurs based on the driving environment of the vehicle or a result ofthe detection of the object and control signal characteristics of thetransmitted radar signal or the received radar signal when thepredetermined event occurs. The process of controlling signalcharacteristics of the transmitted radar signal or the received radarsignal based on whether or not the predetermined event occurs will bedescribed in detail with reference to FIG. 4 to FIG. 6.

FIG. 4 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as curve driving of avehicle, occurs in accordance with an embodiment of the presentdisclosure. Referring to FIG. 4, the driving environment detector 220may detect a steering angle or a yaw rate of a vehicle 400 and detect adriving environment of the vehicle 400 based on the detected steeringangle or yaw rate of the vehicle 400. Herein, the steering angle refersto the angle for steering wheels of the vehicle 400 depending on thedegree of rotation of a handle of the vehicle 400, and the yaw raterefers to the rate of change in rotation angle (yaw angle) around thevertical line passing through the center of the vehicle 400.

The controller 240 may determine whether or not the predetermined event,such as curve driving 440 of the vehicle 400, occurs based on thedetected steering angle or yaw rate of the vehicle 400. Here, the reasonfor determining whether or not the curve driving 440 occurs is that whenthe vehicle 400 turns left at an intersection based on path planning,such as turning left, turning right and U-turn, during autonomousdriving, it is very important to detect a nearby vehicle 430 approachingon the opposite lane.

When the curve driving 440 of the vehicle 400 occurs, the controller 240may control the bandwidth of the transmitted radar signal. For example,the controller 240 may reduce the range resolution by reducing thebandwidth of the transmitted radar signal. Thus, the object detector 230may increase the maximum detection range by controlling the bandwidth ofthe transmitted radar signal.

For example, the transceiver 210 may increase the maximum detectionrange for the medium-distance mode and the long-distance mode byreducing the bandwidth of a radar signal to be transmitted to adetection range 420 in the medium-distance mode and a detection range410 in the long-distance mode.

When the curve driving 440 of the vehicle 400 occurs, the controller 240may control the number of transmitter antennas connected to thetransceiver 210 and used for MIMO operation. The term “MIMO” refers to atechnique using a plurality of antennas for increasing the transmissioncapacity of a radar signal in proportion to the number of antennas.

For example, the controller 240 may reduce the number of transmitterantennas Tx used for MIMO operation. The object detector 230 mayincrease the maximum unambiguous velocity of an object to be detectedusing a radar signal by controlling the number of transmitter antennas.

FIG. 5 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as preceding car followingevent, occurs in accordance with an embodiment of the presentdisclosure. Referring to FIG. 5, the object detector 230 may detectinformation about the distance to an object located in front of avehicle 500, the speed (including the relative speed and the absolutevelocity) of the vehicle 500 and a headway time of the vehicle 500. Theheadway time may refer to the driver's response time in variousenvironments. Here, the object detector 230 may detect information aboutthe distance to an object, the speed of the vehicle 500 and a headwaytime of the vehicle 500 in consideration of the current position of thevehicle 500 (for example, at an intersection, tunnel or the like).

The controller 240 may determine whether or not a predetermined event,such as tracking of a preceding vehicle 520, occurs based on thedetected information.

When the preceding car following event occurs, the controller 240 maycontrol the number of samples N_(R) for the received radar signal. Forexample, when the preceding car following event occurs, the controller240 may reduce the number of samples N_(R) for the received radarsignal. The object detector 230 may reduce a maximum detection range 510for the medium-distance mode and the long-distance mode and the cycletime of the transmitted radar signal for the medium-distance mode andthe long-distance mode by controlling the number of samples.

Accordingly, the maximum detection range 510 and the cycle time of aradar signal can be reduced by controlling the number of samples for thereceived radar signal based on the occurrence of preceding car followingevent. Therefore, it is possible to quickly detect the preceding vehicle520 and thus possible to quickly perform an emergency collisionavoidance such as autonomous emergency braking (AEB).

FIG. 6 is an example depiction to explain a process of determiningwhether or not a predetermined event, such as preceding car absenceevent, occurs in accordance with an embodiment of the presentdisclosure. Referring to FIG. 6, the object detector 230 may detectinformation about the distance to an object located in front of avehicle 600, the speed of the vehicle 600 and a headway time of thevehicle 600.

The controller 240 may determine whether or not a predetermined event,such as preceding car absence event, occurs based on the detectedinformation.

When the preceding car absence event occurs, the controller 240 maycontrol the number of samples for the received radar signal or thebandwidth of the transmitted radar signal. Also, the controller 240 maycontrol the bandwidth of the transmitted radar signal based on thedriving speed of the vehicle 600. The object detector 230 may increasethe maximum detection range by controlling the number of samples for thereceived radar signal or the bandwidth of the transmitted radar signal.

For example, when the preceding car absence event occurs (i.e., there isno vehicle detected within a detection range 610 in the medium-distancemode and a detection range 610 in the long-distance mode), thecontroller 240 may reduce the range resolution to reduce the bandwidthof a radar signal to be transmitted or increase the number of samplesfor the received radar signal to increase the maximum detection rangefor the medium-distance mode and the long-distance mode in a drivingdirection of the vehicle 600.

When the preceding car absence event occurs, the controller 240 maycontrol the number of transmitter antennas connected to the transceiver210 and used for MIMO operation. For example, the controller 240 mayreduce the number of transmitter antennas Tx used for MIMO operation.The object detector 230 may increase the maximum unambiguous velocity ofan object to be detected using a radar signal by controlling the numberof transmitter antennas connected to the transceiver.

The controller 240 may control the number of transmitter antennas basedon the driving speed of a vehicle. For example, the controller 240 mayreduce the bandwidth of a radar signal to be transmitted and the numberof transmitter antennas Tx used for MIMO operation as the driving speedof the vehicle 600 increases. Thus, the controller 240 may increase themaximum detection range for the medium-distance mode and thelong-distance mode. The object detector 230 may increase the maximumunambiguous velocity of an object to be detected using a radar signal bycontrolling the number of transmitter antennas connected to thetransceiver.

FIG. 7 is a flowchart showing a method for detecting an object by theobject detection radar apparatus in accordance with an embodiment of thepresent disclosure. The method for detecting an object by the objectdetection radar apparatus 200 illustrated in FIG. 7 includes theprocesses time-sequentially performed by the object detection radarapparatus 200 according to the embodiment illustrated in FIG. 2 to FIG.6. Therefore, descriptions of the processes performed by the objectdetection radar apparatus 200 may also be applied to the method fordetecting an object by the object detection radar apparatus 200, eventhough they are omitted hereinafter.

In a process 5710, the object detection radar apparatus 200 may transmita radar signal to the outside of a vehicle.

In a process 5720, the object detection radar apparatus 200 may receivea radar signal reflected from an object.

In a process 5730, the object detection radar apparatus 200 may detect adriving environment of the vehicle based on an operation status of thevehicle.

In a process 5740, the object detection radar apparatus 200 may detectthe object based on the received radar signal.

In a process 5750, the object detection radar apparatus 200 maydetermine whether or not a predetermined event occurs based on thedriving environment of the vehicle or a result of the detection of theobject.

In a process 5760, the object detection radar apparatus 200 may controlsignal characteristics of the transmitted radar signal or the receivedradar signal when the predetermined event occurs.

In the descriptions above, the processes 5710 to 5760 may be dividedinto additional processes or combined into fewer processes depending onan embodiment. In addition, some of the processes may be omitted and thesequence of the processes may be changed if necessary.

The method for detecting an object by the object detection radarapparatus illustrated in FIG. 2 to FIG. 7 can be implemented as acomputer program stored in a medium to be executed by a computer or astorage medium including instructions codes executable by a computer.Also, the method for detecting an object by the object detection radarapparatus illustrated in FIG. 2 to FIG. 6 can be implemented as acomputer program stored in a medium to be executed by a computer.

A computer-readable medium can be any usable medium which can beaccessed by the computer and includes all volatile/non-volatile andremovable/non-removable media. Further, the computer-readable medium mayinclude all computer storage and communication media. The computerstorage medium includes all volatile/non-volatile andremovable/non-removable media embodied by a certain method or technologyfor storing information such as computer-readable instruction code, adata structure, a program module or other data. The communication mediumtypically includes the computer-readable instruction code, the datastructure, the program module, or other data of a modulated data signalsuch as a carrier wave, or other transmission mechanism, and includes acertain information transmission medium.

The above description of the present disclosure is provided for thepurpose of illustration, and it would be understood by those skilled inthe art that various changes and modifications may be made withoutchanging technical conception and essential features of the presentdisclosure. Thus, it is clear that the above-described embodiments areillustrative in all aspects and do not limit the present disclosure. Forexample, each component described to be of a single type can beimplemented in a distributed manner. Likewise, components described tobe distributed can be implemented in a combined manner.

The scope of the present disclosure is defined by the following claimsrather than by the detailed description of the embodiment. It shall beunderstood that all modifications and embodiments conceived from themeaning and scope of the claims and their equivalents are included inthe scope of the present disclosure.

What is claimed is:
 1. An object detection radar apparatus that isinstalled in a vehicle and configured to detect an object, comprising: atransceiver configured to transmit a radar signal to an outside of thevehicle and receive a radar signal reflected from the object; a drivingenvironment detector configured to detect a driving environment of thevehicle based on an operation status of the vehicle; an object detectorconfigured to detect the object based on the received radar signal; anda controller configured to: determine whether or not a predeterminedevent occurs based on the driving environment of the vehicle or a resultof the detection of the object, and control signal characteristics ofthe transmitted radar signal or the received radar signal when thepredetermined event occurs.
 2. The object detection radar apparatus ofclaim 1, wherein the driving environment detector detects a steeringangle or a yaw rate of the vehicle, and the controller determineswhether or not curve driving of the vehicle occurs based on the detectedsteering angle or yaw rate of the vehicle.
 3. The object detection radarapparatus of claim 2, wherein when the curve driving of the vehicleoccurs, the controller controls a bandwidth of the transmitted radarsignal.
 4. The object detection radar apparatus of claim 3, wherein theobject detector increases a maximum detection range by controlling thebandwidth of the transmitted radar signal.
 5. The object detection radarapparatus of claim 2, wherein when the curve driving of the vehicleoccurs, the controller controls the number of transmitter antennasconnected to the transceiver and used for multi-input multi-output(MIMO) operation.
 6. The object detection radar apparatus of claim 5,wherein the object detector increases a maximum unambiguous velocity bycontrolling the number of transmitter antennas.
 7. The object detectionradar apparatus of claim 1, wherein the object detector detects at leastone of information about a distance to an object located in front of thevehicle, a speed of the vehicle and a headway time of the vehicle, andthe controller determines whether or not a preceding car following eventoccurs based on the detected information.
 8. The object detection radarapparatus of claim 7, wherein when the preceding car following eventoccurs, the controller controls the number of samples for the receivedradar signal.
 9. The object detection radar apparatus of claim 8,wherein the object detector reduces a maximum detection range and acycle time of the transmitted radar signal by controlling the number ofsamples.
 10. The object detection radar apparatus of claim 1, whereinthe object detector detects at least one of information about a distanceto an object located in front of the vehicle, a speed of the vehicle anda headway time of the vehicle, and the controller determines whether ornot a preceding car absence event occurs based on the detectedinformation.
 11. The object detection radar apparatus of claim 10,wherein when the preceding car absence event occurs, the controllercontrols the number of samples for the received radar signal or abandwidth of the transmitted radar signal.
 12. The object detectionradar apparatus of claim 11, wherein the controller controls thebandwidth of the transmitted radar signal based on a driving speed ofthe vehicle.
 13. The object detection radar apparatus of claim 11,wherein the object detector increases a maximum detection range bycontrolling the number of samples for the received radar signal or thebandwidth of the transmitted radar signal.
 14. The object detectionradar apparatus of claim 10, wherein when the preceding car absenceevent occurs, the controller controls the number of transmitter antennasconnected to the transceiver and used for MIMO operation.
 15. The objectdetection radar apparatus of claim 14, wherein the controller controlsthe number of transmitter antennas based on the driving speed of thevehicle.
 16. The object detection radar apparatus of claim 14, whereinthe object detector increases a maximum unambiguous velocity bycontrolling the number of transmitter antennas connected to thetransceiver.
 17. An object detection method for detecting an object,comprising: transmitting a radar signal to the outside of a vehicle;receiving a radar signal reflected from the object; detecting a drivingenvironment of the vehicle based on an operation status of the vehicle;detecting the object based on the received radar signal; determiningwhether or not a predetermined event occurs based on the drivingenvironment of the vehicle or a result of the detection of the object;and controlling signal characteristics of the transmitted radar signalor the received radar signal when the predetermined event occurs.